The expectation for any configuration of chemical/biochemical reactor is the presence of efficient mixing to enhance heat and mass transfer as needed for the application of interest. In the past decade, Oscillatory Flow (OF) has been implemented in chemical reactors to increase the heat transfer and mass transfer in a process, while maintaining plug-flow behavior. This technology has not yet been extended to mini-fluidic devices, and is being explored as a novel approach for enhanced passive mixing at mini/micro scales. As a preliminary step in process intensification of OF technology, this work explores the fundamental working principles of operation and extension of conventional correlations applied to mini-fluidic scales. The theoretical calculations of energy dissipation versus mixing are compared to existing mini-fluidic mixers in literature, illustrating the need to develop novel mixing geometries that take advantage of the OF field. The preliminary experimental results are provided for an OF generator, intended for use in subsequent experiments exploring mini-fluidic mixers with OF technology.

The requirement for any configuration of a chemical/biochemical reactor is the presence of efficient mixing to enhance heat and mass transfer as needed for the application of interest. Furthermore, as an Oscillatory Flow (OF) reactor has a combination of flow oscillation and baffled tube configuration, it has the potential to ensure the efficient mixing and effective heat and mass transfer (Stonestreet and Harvey, 2002). It has been observed that an OF Reactor (OFR) improved both conversion and selectivity of the relevant reaction by efficient mixing. However, this technology has not yet been extended to mini-fluidic devices, and is being explored as a novel approach for enhanced mixing at reduced scales. This work explores the application of OF Technology (OFT) in mini-fluidics. As a preliminary step in the process intensification of OFT in mini-channels, the Nusselt number and pressure drop are predicted and compared to smooth pipes. Theoretical calculations of energy dissipation versus mixing are comparable to existing mini-fluidic mixers in literature, illustrating the need to develop novel mixing geometries. Limited research has been performed for oscillatory and pulsatile flow in mini-channels due to different mechanism in mixing and the potential of OF in mini-channels to boost heat and mass transfer. The process intensification of OFR in mini-channels may increase the performance of reactor such as selectivity and yield though improved plug-flow behavior (Harvey et al., 2003). The conventional OFR has been used in many chemical processing and engineering applications such as biodiesel, protein folding and gas-liquid operations. It has been observed that the oscillatory motion creates eddies that lead to uniform efficient mixing than that of conventional stirred tank reactor. Further, it has low and uniform shear, increased heat and mass transfer, compact design and easy to scale up. The present analysis proves that OFR in mini-channel improves the momentum and heat transfer than smooth mini-channel with absence of OFT.

Mechanical Engineering Journal, Oscillatory flow reactor, Mini-fluidics, Process intensification, Oscillatory Flow (OF), OF Technology (OFT).